Bulb-type light source

ABSTRACT

A lighting device includes a substrate having a plurality of flat portions and a non-flat portion disposed between the flat portions, a plurality of light emitting sources disposed on the substrate, a fluorescent substrate layer covering one or more light emitting sources and converting a wavelength of a light from the light emitting source, and a connection line disposed on the substrate and electrically connecting the light emitting sources adjacent to each other between the adjacent light emitting sources. The substrate has a first end and a second end are arranged at different distance from a central axis.

CROSS-REFERENCE OF RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/822,312 filed Mar. 18, 2020, which is a continuation of PCTApplication No. PCT/KR2018/013157 filed Nov. 1, 2018, entitled “BULBTYPE LIGHT SOURCE,” which claims priorities and the benefits of KoreanPatent Application No. 10-2017-0155075 entitled “BULB TYPE LIGHT SOURCE”filed on Nov. 20, 2017. The contents of each application noted above areincorporated by reference in their entirety.

TECHNICAL FIELD

Various embodiments disclosed in the present disclosure relate to abulb-type light source having a bulb shape, and more particularly,relate to a bulb-type light source including a light emitting device.

BACKGROUND

Conventionally, a light bulb employing a filament as its light source isbeing used; however, the light bulb is being gradually replaced with alight emitting device, such as a light emitting diode, as the light bulbemploying the filament has low light amount and high power consumption.When the light emitting device is used, the light emitting device ismade to have the look and shape of a conventional filament for adecorative purpose. For instance, the light emitting device may bedesigned to have the same shape as a conventional filament bulb.

However, in the case where the light source having the same shape as theconventional filament bulb is manufactured using the light emittingdevice, a light emitting direction may be limited.

SUMMARY

A lighting device according to various embodiments of the presentdisclosure includes a substrate having a plurality of flat portions anda non-flat portion disposed between the flat portions, a plurality oflight emitting sources disposed on the substrate, a fluorescentsubstrate layer covering one or more light emitting sources andconverting a wavelength of a light from the light emitting source, and aconnection line disposed on the substrate and electrically connectingthe light emitting sources adjacent to each other between the adjacentlight emitting sources. The substrate has a first end and a second endare arranged at different distance from a central axis.

In at least one variation, the lighting device further includes a gloveto transmit a light emitted from the light emitting source.

In another variant, the lighting device further includes a socketengaged with the globe and a power board disposed in the socket andconnected to the light emitting source.

In further another variant, the first end of the substrate is connectedto the power board, and the second end of the substrate is spaced apartfrom the power board.

In another variant, the plurality of light emitting sources are arrangedradially about a center of the glove when viewed from one direction.

In another variant, the first end of the substrate is farther away fromthe center than the second end of the substrate is.

In another variant, the substrate is farther away from the center at aposition between the first and second ends than from the first andsecond ends.

In another variant, the lighting device further includes a fixing platethat fixes the second end.

In another variant, each light emitting source emits light with anorientation angle in two or more light emission areas, and two lightemission areas are positioned at the second ends adjacent to each otherand overlap with each other. A distance from the fixing plate to theoverlapping area is smaller than a distance from the fixing plate to theglobe.

In another variant, an electrode pad is disposed at the first end tosupply power to the light emitting sources.

A lighting device according to embodiments of the present disclosure,includes a globe transmitting a light, a substrate comprising aplurality of flat portions and at least one of non-flat portion, aplurality of light emitting sources disposed on the substrate, afluorescent substrate layer covering one or more light emitting sourcesand converting a wavelength of a light from the light emitting source,and a connection line disposed on the substrate and electricallyconnecting the light emitting sources adjacent to each other between theadjacent light emitting sources. The substrate has a first end and asecond end, the first end and the second end arranged at differentdistance from a central axis.

In at least one variant, the lighting device further includes a socketengaged with the globe, and a power board disposed in the socket andconnected to the light emitting source.

In another variant, the first end of the substrate is connected to thepower board, and the second end of the substrate is spaced apart fromthe power board.

In further another variant, the plurality of light emitting sources arearranged radially about a center of the glove when viewed from onedirection.

In another variant, the first end of the substrate is farther away fromthe center than the second end of the substrate is.

In another variant, the substrate is farther away from the center at aposition between the first and second ends than from the first andsecond ends.

The lighting device further includes a fixing plate that fixes thesecond end.

In another variant, each light emitting source emits a light with anorientation angle in two or more light emission areas, and two lightemission areas are positioned at the second ends adjacent to each otherand overlap with each other. A distance from the fixing plate to theoverlapping area is smaller than a distance from the fixing plate to theglobe.

In another variant, an electrode pad is disposed at the first end tosupply a power to the light emitting sources.

In another variant, the power board is provided with an insertion holeinto which the first end is inserted, and the power is supplied to thelight emitting device chips through the electrode pad when the first endis inserted into the insertion hole.

Various embodiments disclosed in the present disclosure provide abulb-type light source having the same shape as a conventional lightbulb and having a light emitting device filament having good lightuniformity in all directions.

A bulb-type light source according to various embodiments of the presentdisclosure includes a globe transmitting a light and at least one lightemitting device filament disposed in the globe. The light emittingdevice filament includes a substrate including n (n is a natural numberequal to or greater than 2) flat portions and n−1 bendable portionsdisposed between the flat portions, a plurality of light emitting devicechips disposed on the flat portions, a fluorescent substance layercovering the light emitting device chip and converting a wavelength of alight from the light emitting device chip, and a connection linedisposed on the flat portions and electrically connecting the lightemitting device chips adjacent to each other between the adjacent lightemitting device chips.

The substrate includes at least one notch defined in the bendableportions, and at least one light emitting device chip is disposed ineach flat portion.

The connection line has different widths from each other at the bendableportion. The connection line has a zigzag shape at the bendable portion.

The fluorescent substance layer is disposed at, at least a portion ofthe flat portion and covers the light emitting device chips. Thefluorescent substance layer extends from the flat portion and covers thebendable portion. The fluorescent substance layer is bent at thebendable portion. The fluorescent substance layer has differentthicknesses in the flat portions and the bendable portion.

At least one flat portion among the flat portions has a length differentfrom the other flat portions.

The notch is provided along a width direction of the light emittingdevice filament. The notch is provided along a longitudinal direction ofthe light emitting device filament. The notch is provided to be inclinedwith respect to a longitudinal direction of the light emitting devicefilament.

The bulb-type light source further includes a socket engaged with theglobe and a power board disposed in the socket and connected to thelight emitting device filament.

A first end of the light emitting device filament is connected to thepower board, and a second end of the light emitting device filament isspaced apart from the power board.

The light emitting device filament is provided in plural, and the lightemitting device filaments are arranged radially about a center of theglove when viewed from one direction.

The first end of the light emitting device filament is farther away fromthe center than the second end of the light emitting device filament is.

The light emitting device filament is farther away from the center at aposition between the first and second ends than at the first and secondends.

The bulb-type light source further includes a fixing plate that fixesthe second ends.

When each light emitting device chip emits a light with an orientationangle, light emission areas in the orientation angle of the lightemitting device chips, which are positioned at the second ends adjacentto each other, overlap each other, and a distance from the fixing plateto the overlapping area is smaller than a distance from the fixing plateto the globe.

An electrode pad is disposed at the first end to supply a power to thelight emitting device chips.

The power board is provided with an insertion hole into which the firstend is inserted, and the power is supplied to the light emitting devicechips through the electrode pad when the first end is inserted into theinsertion hole.

Other aspects, advantages, and salient features of the presentdisclosure will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses various embodiments of the presentdisclosure.

According to an exemplary embodiment of the present disclosure, thebulb-type light source with the shape similar to that of theconventional bulb but with the high light uniformity in all directionsis provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a bulb-type light source accordingto an exemplary embodiment of the present disclosure;

FIG. 2A is a side cross-sectional view showing a bulb-type light sourceaccording to an exemplary embodiment of the present disclosure;

FIG. 2B is a top view showing a bulb-type light source according to anexemplary embodiment of the present disclosure;

FIG. 3A is a plan view showing a light emitting device filamentaccording to an exemplary embodiment of the present disclosure;

FIG. 3B is a side view showing the light emitting device filament ofFIG. 3A;

FIG. 3C is a side view showing the light emitting device filament ofFIG. 3B having a bendable portion in a bent shape;

FIG. 4A is an enlarged side cross-sectional view showing a portion P1 ofFIG. 3B;

FIG. 4B is an enlarged side cross-sectional view showing a portion P2 ofFIG. 3B;

FIG. 4C is an enlarged side cross-sectional view showing a portion P2 ofFIG. 3B with an additional line;

FIG. 5 is a cross-sectional view showing a light emitting device chipimplemented using a light emitting diode according to an exemplaryembodiment of the present disclosure;

FIG. 6A is a conceptual view showing a plurality of light emittingdevices connected to a connection line in parallel according to anexemplary embodiment of the present disclosure;

FIG. 6B is a conceptual view showing a plurality of light emittingdevices connected to a connection line in series according to anexemplary embodiment of the present disclosure;

FIG. 7 is a side cross-sectional view showing a portion of a bulb-typelight source employing a light emitting device filament according to anexemplary embodiment of the present disclosure;

FIG. 8A is a perspective view showing a bendable portion and two flatportions adjacent to a bendable portion of a bulb-type light sourceaccording to an exemplary embodiment of the present disclosure;

FIG. 8B is a perspective view showing a bendable portion having adifferent shape from the bendable portion of FIG. 8A and two flatportions adjacent to the bendable portion of a bulb-type light sourceaccording to an exemplary embodiment of the present disclosure;

FIG. 9A is a cross-sectional view showing a first type of bendableportion;

FIG. 9B is a cross-sectional view showing a second type of bendableportion;

FIG. 9C is a cross-sectional view showing a third type of bendableportion;

FIG. 9D is a cross-sectional view showing a fourth type of bendableportion;

FIG. 9E is a cross-sectional views showing a fifth type of bendableportion;

FIG. 10A is a plan view showing a light emitting device filamentaccording to another exemplary embodiment of the present disclosure;

FIG. 10B is a side view showing the light emitting device filament ofFIG. 10A;

FIG. 10C is a side view showing the light emitting device filament ofFIG. 10B in a bent shape;

FIG. 11A is a plan view showing a light emitting device filamentaccording to another exemplary embodiment of the present disclosure;

FIG. 11B is a cross-sectional view taken along a line I-I′ of FIG. 11A;

FIG. 12A is a plan view showing a light emitting device filamentaccording to an exemplary embodiment of the present disclosure;

FIG. 12B is a view showing a bulb-type light source manufactured usingthe light emitting device filament of FIG. 12A;

FIG. 13A is a cross-sectional view showing a first type of globe;

FIG. 13B is a cross-sectional view showing a second type of globe;

FIG. 13C is a cross-sectional view showing a third type of globe; and

FIG. 14 is a view showing a bulb-type light source according to anexemplary embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure may be variously modified and realized in manydifferent forms, and thus, specific embodiments will be exemplified inthe drawings and described in detail hereinbelow. However, the presentdisclosure should not be limited to the specific disclosed forms, and beconstrued to include all modifications, equivalents, or replacementsincluded in the spirit and scope of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to accompanying drawings. FIG. 1 is a perspectiveview showing a bulb-type light source according to an exemplaryembodiment of the present disclosure. FIG. 2A is a side cross-sectionalview showing a bulb-type light source according to an exemplaryembodiment of the present disclosure. FIG. 2B is a top view showing abulb-type light source according to an exemplary embodiment of thepresent disclosure.

Referring to FIGS. 1, 2A, and 2B, the bulb-type light source accordingto the exemplary embodiment of the present disclosure includes a globe20 provided with an opening defined through one side thereof and formedof a light transmitting material, a light emitting device filament 10disposed in the globe 20, a power board 30 connected to one end of thelight emitting device filament 10, and a socket 40 connected to theopening of the globe 20 and the power board 30.

The globe 20 has a spherical shape as a whole and has the opening forinserting the light emitting device filament 10, which is definedthrough one side thereof. The globe 20 may have a complete or incompletespherical shape except for a portion for the opening, but it should notbe limited thereto or thereby. The globe 20 may have a variety ofshapes, such as an oval shape, or a shape of which a portion protrudes.The opening may vary depending on the shape of the globe 20 and may havea circular or oval shape.

The globe 20 includes the light transmitting material to transmit alight emitted from the light emitting device filament 10. Here, thephrase, “light transmitting” means that the globe 20 transmits at leasta portion of the light emitted from the light emitting device filament10 in the globe 20, including the situations where the globe 20 issemi-transparent to transmit only a light having a specific wavelength,or only a portion of a light of a specific wavelength, or where theglobe 20 is partially transparent. In addition, the phrase, “lighttransmitting” includes the situation where the globe 20 is transparentto transmit all the light. To this end, the globe 20 may be formed of atransparent or semitransparent glass to transmit at least a portion ofthe light. However, a material for the globe 20 should not be limitedthereto or thereby, and the globe 20 may be formed of a plasticmaterial.

The light emitting device filament 10 is a filament-shaped component andincludes a substrate and a light emitting device chip provided on thesubstrate. The light emitting device filament 10 emits the light. Thelight emitted from the light emitting device filament 10 transmitsthrough the globe 20 that is transparent and then travels to the outsideof the globe 20.

The light emitting device filament 10 is provided in a form that isinserted into the globe 20 through the opening of the globe 20. Thelight emitting device filament 10 may be provided in an elongated barshape. One end in a longitudinal direction of the light emitting devicefilament 10 is referred to as a “first end” 111 a and the other endopposite to the first end 111 a in the longitudinal direction isreferred to as a “second end” 111 b, as shown in FIG. 2A.

One or more light emitting device filaments 10 may be provided, forexample, about two to about five. In the exemplary embodiment of thepresent disclosure, four light emitting device filaments 10 areprovided. However, a number of the light emitting device filaments 10should not be limited thereto or thereby, and the light emitting devicefilaments 10 may be provided in a greater number than theabove-mentioned number depending on a size or brightness of thebulb-type light source.

Assuming that an imaginary line extending in a direction in which thesocket 40 is engaged with the globe 20 is referred to as a “centralaxis” CL, the light emitting device filament 10 is engaged with thesocket 40 and the power board 30 in the form of extending along thecentral axis CL. The light emitting device filament 10 may be bentmultiple times and may have a bent shape such that a portion thereof isaway from the central axis CL. That is, as shown in figures, the firstend 111 a and the second end 111 b are arranged at a relatively smalldistance from the central axis CL. However, an area between the firstend 111 a and the second end 111 b is arranged at a relatively largedistance from the central axis CL. In addition, distances between thecentral axis CL and the light emitting device filament 10 at the firstend 111 a and the second end 111 b may also be different from eachother, and the distance between the central axis CL and the lightemitting device filament 10 at the first end 111 a may be greater thanthe distance between the central axis CL and the light emitting devicefilament 10 at the second end 111 b.

A distance between the central axis CL and the light emitting devicefilament 10 closest to the central axis CL at the first end 111 a in avertical direction of the central axis CL is referred to as a firstdistance d1, a distance between the central axis CL and the lightemitting device filament 10 closest to the central axis CL at the secondend 111 b in the vertical direction of the central axis CL is a seconddistance d2, and a distance between the central axis CL and the lightemitting device filament 10 in the vertical direction of the centralaxis CL in the area between the first and second ends 111 a and 111 b isa third distance d3. The third distance d3 may be greater than the firstdistance d1 and/or the second distance d2. In addition, the firstdistance d1 may be greater than the second distance d2. In the exemplaryembodiment, the light emitting device filament 10 is farthest away fromthe central axis CL in the area between the first end 111 a and thesecond end 111 b, so that an influence of heat between light emittingdevice filaments 10 adjacent to each other is minimized. In particular,as a diameter of the globe 20 is the largest in an area corresponding tothe area between the first end 111 a and the second end 111 b, eventhough the heat is dissipated from the light emitting device filament10, not only the influence on the adjacent light emitting devicefilament 10 becomes small but also a heat dissipation toward the globe20 disposed at an outer side of the light emitting device filament 10 iseasy. Further, when the diameter of the globe 20 is larger than otherareas, an amount of heat accumulated in a unit space area may bereduced. Accordingly, a heat dissipation effect is maximized byarranging the light emitting device filament 10 to be the farthest awayfrom the central axis CL in the area between the first end 111 a and thesecond end 111 b where the diameter of the globe 20 is the largest.

In the exemplary embodiment of the present disclosure, as the thirddistance d3 is greater than the first distance d1 and/or the seconddistance d2, the transfer of heat adjacent to the light emitting devicefilament 10 may be minimized. In addition, since the first distance d1is greater than the second distance d2, heat generated by the lightemitting device filament 10 may be easily distributed or dissipatedthrough the power board 30 (or a separate heat dissipation boardprovided under the power board 30).

In the exemplary embodiment of the present disclosure, when the lightemitting device filament 10 is provided in plural, the light emittingdevice filaments 10 may be arranged radially with respect to the centralaxis when viewed from the top perpendicular to the central axis CL. Inaddition, angles between the radially disposed light emitting devicefilaments 10 may be substantially equal to each other. Therefore, thelight emitted from the light emitting device filament 10 may travel asuniformly as possible in all directions of 360 degrees with respect tothe central axis CL. However, according to another exemplary embodimentof the present disclosure, in a case where an emission direction isrequired to be anisotropic, it is not necessary to arrange the lightemitting device filaments 10 radially at equal intervals, and the lightemitting device filaments 10 may be further arranged along a particulardirection in which the light is directed.

The power board 30 is connected to the first end 111 a of the lightemitting device filament 10, and the power board 30 supplies a power tothe light emitting device filament 10. The second end 111 b of the lightemitting device filament 10 is spaced apart from the power board 30.

The power board 30 is disposed at the opening of the globe 20 andencapsulates the opening of the globe 20 together with the socket 40.The power board 30 may have a variety of shapes and may fix the lightemitting device filament 10 while supplying the power to the lightemitting device filament 10. In the exemplary embodiment of the presentdisclosure, the power board 30 may have a circular plate shape having astep difference. However, the shape of the power board 30 may varydepending on the shape and structure of the globe 20 and the socket 40and the connection structure to the light emitting device filament 10.

An insertion hole 31 may be defined in the power board 30, and the firstend 111 a of the light emitting device filament 10 may be inserted intoand fixed to the insertion hole 31. The insertion hole 31 may beprovided in a number corresponding to the number of the light emittingdevice filaments 10. A wire connection portion may be disposed insidethe insertion hole 31 of the power board 30 to be electrically connectedto an electrode pad disposed at the first end 111 a of the lightemitting device filament 10, and the wire connection portion iselectrically connected to the electrode pad disposed at the first end111 a of the light emitting device filament after the light emittingdevice filament 10 is inserted.

Although not shown in the figures such as FIGS. 1 and 2A-2B, the powerboard 30 may further include a heat sink for the dissipation in aposition adjacent to the electrode pad. The kind or shape of the heatsink should not be particularly limited and may have various known kindsor shapes.

A fixing plate 11 may be provided at the second end 111 b of the lightemitting device filament 10. The fixing plate 11 may be provided toallow the central axis CL to pass through a center portion thereof. Whenthere are plural light emitting device filaments 10, the fixing plate 11may serve to collect and fix the second ends 111 b of the light emittingdevice filaments 10. For example, the fixing plate 11 may have groovesin which the second ends 111 b are mounted, respectively, and the secondends 111 b may be stably supported with each other by being fitted inthe grooves. Thus, although external impacts are applied to thebulb-type light source, a structure that is designed to be free of darkspots may be maintained as a gap between the second ends 111 b is notexcessively widened or narrowed. When the light emitting devicefilaments 10 are not sufficiently stably fixed, one end of the elongatedlight emitting device filament 10 may be shaken when being applied withthe external impact, and the light emitting device filament 10 maycollide with another light emitting device filament adjacent thereto toapply a secondary shock, thereby causing a defect, but the fixing plate11 prevents the defect. However, when the light emitting device filament10 is sufficiently firmly fixed and there is not much shaking due to theexternal impact, the fixing plate 11 may be omitted.

The socket 40 is engaged with the power board 30 and provided with anengaging member to be mounted on an external device (e.g., an electricaloutlet). The socket 40 may include a screw thread contact 41 engagedwith the opening of the glove 20 and an electrical foot contact 43protruded downward. The screw thread contact 41 and the electrical footcontact 43 may include a conductive material, but it may be insulatedfrom each other. In this case, the screw thread contact 41 and theelectrical foot contact 43 are connected to the electrode pad of thelight emitting device filament 10, and the power is applied to the lightemitting device filament 10 via the screw thread contact 41 and theelectrical foot contact 43. However, the screw thread contact 41 and theelectrical foot contact 43 are not necessarily formed of the conductivematerial in the case where the screw thread contact 41 and theelectrical foot contact 43 are made to resemble an old bulb merely foraesthetic appearance. In this case, a power supply formed of aconductive material, such as a connector, may be provided separately inaddition to the screw thread contact and the electrical foot contact.

FIGS. 3A to 3C are views showing a light emitting device filamentaccording to an exemplary embodiment of the present disclosure. FIG. 3Ais a plan view showing the light emitting device filament, and FIGS. 3Band 3C are side views showing the light emitting device filament.

FIG. 4A is an enlarged side cross-sectional view showing a portion P1 ofFIG. 3B, and FIGS. 4B and 4C are enlarged side cross-sectional viewsshowing a portion P2 of FIG. 3B. For the convenience of explanation,FIGS. 3A and 3B show a state before the light emitting device filamentis bent, and FIG. 3C shows a state after the light emitting devicefilament is bent.

Referring to FIGS. 3A to 3C and 4A to 4C, the light emitting devicefilament according to the exemplary embodiment of the present disclosureis elongated in one direction and has the bar shape with a first end 111a and a second end 111 b.

The light emitting device filament 10 includes the substrate 110 and thelight emitting device chip 130 (FIGS. 4A through 4C) disposed on thesubstrate 110. The substrate 110 has a bar shape elongated in onedirection and is bent at least one time. The substrate 110 includes aconductive material, for example, a single metal of Al, Zn, Ag, W, Ti,Ni, Au, Mo, Pt, Pd, Cu, Cr or Fe, or an alloy thereof. In the exemplaryembodiment of the present disclosure, the substrate 110 may includealuminum.

The substrate 110 includes a bendable portion 113 defined by bending aportion thereof and at least two flat portions R1, R2, R3, . . . , andRn adjacent to each other with the bendable portion 113 disposedtherebetween. Since the bendable portion 113 is disposed between theflat portions R1, R2, R3, . . . , and Rn adjacent to each other, thenumber of the flat portions R1, R2, R3, . . . , and Rn is one more thanthe number of the bendable portions 113. In other words, when the numberof the flat portions R1, R2, R3, R4, . . . , Rn is “n” (n is a naturalnumber of two or more), the number of the bendable portions 113 is“n−1”.

A notch 115 having a shape recessed in a direction opposite to at leastone surface of the substrate 110 is formed in the bendable portion 113.In the present exemplary embodiment, the notch 115 may have a shaperecessed along a width direction of the substrate 110 and may have atriangular shape in a cross-section.

Two or more bendable portions 113, are provided in the substrate 110.Although not shown in figures, when there are components, such as afilm, formed on the bendable portion 113, not only the substrate 110 ofthe bendable portion 113 but also other components on the bendableportion 113 have the bent shape.

In the exemplary embodiment of the present disclosure, the flat portionsR1, R2, R3, . . . , Rn correspond to substantially a flat straight area.In the exemplary embodiment of the present disclosure, the flat portionsR1, R2, R3, R4, . . . , and Rn may not be provided in a straight-lineshape, and at least some of the flat portions R1, R2, R3, R4, . . . ,and Rn may be bent as needed. In this case, however, the substrate 110may not be completely flexible and may include a relatively rigidmaterial to have a flat shape.

As shown in FIG. 3B, the notch 115 is provided to allow the substrate110 to be easily bent. In the present exemplary embodiment, the notch115 may have a shape recessed along the width direction of the substrate110.

A thickness of the substrate 110 in the area where the notch 115 isformed is smaller than a thickness of the substrate 110 in the areawhere the notch 115 is not formed. Accordingly, the substrate 110 may beeasily bent in the area where the notch 115 is formed.

The substrate 110 is configured to be more readily bendable toward thesurfaces having the notch 115 formed therein according to the positionand the shape of the notch 115. This is because space formed from thenotches 115 can be used to allow bending of the substrate 110. Due tothe notches 115, the substrate 110 may not be configured to bend in theopposite direction, i.e., toward the surface that the notches 115 arenot formed, as the substrate 110 is pulled away relative to the notches115 for bending. In the exemplary embodiment of the present disclosure,the notch 115 may be defined in a lower surface of the substrate 110,and the substrate 110 may be bent toward the lower surface thereof suchthat a portion of the lower surface becomes closer to another portion ofthe lower surface in a direction facing each other.

The flat portions R1, R2, R3, R4, . . . , and Rn may have a relativelyflat shape compared with the bendable portion 113. The number of theflat portions R1, R2, R3, R4, . . . , and Rn and the number of thenotches 115 may be provided in one or more depending on the shape of thesubstrate 110 to be finally formed. In the present exemplary embodiment,four flat portions R1, R2, R3, R4, . . . , and Rn, i.e., n=4, and threebendable portions 113 are shown. However, as described above, the numberof the flat portions R1, R2, R3, R4, . . . , and Rn and the number ofthe bendable portions 113 should not be limited thereto or thereby andmay be provided in various numbers. In the following drawings, asubstrate including first, second, third, and fourth flat portions willbe described as a representative example.

The flat portions R1, R2, R3, R4, . . . , and Rn may be sequentiallyarranged from the first end 111 a. The flat portions R1, R2, R3, R4, . .. , and Rn may have the same length as each other or may have differentlengths from each other. That is, the length of at least one flatportion among the flat portions R1, R2, R3, R4, . . . , and Rn may havea value different from those of the other flat portions among the flatportions R1, R2, R3, R4, . . . , Rn. The length of each of the flatportions R1, R2, R3, R4, . . . , and Rn may vary depending on a finaldesired shape of the light emitting device filament 10, i.e., how muchbending of the light emitting device filament is desired. For example,in the exemplary embodiment of the present disclosure, when the lengthsof the flat portions R1, R2, R3, R4, . . . , Rn are respectivelyreferred to as lengths L1, L2, L3, L4, . . . , and Ln, the lengths L1,L2, L3, L4, . . . , and Ln may have values that sequentially decreases.

According to the lengths of the flat portions R1, R2, R3, R4, . . . ,and Rn, the bent shape is changed, and an overall shape of the substrate110 is changed. When the number of the bendable portions 113 provided ina predetermined area increases, the bending of the substrate 110increases, and thus, a shape of the light emitting device filament 10eventually becomes similar to a shape that has a small radius ofcurvature as a whole, though it is not a curved line. On the contrary,when the number of the bendable portions 113 provided in a predeterminedarea decreases, the shape of the substrate 110 becomes similar to astraight line and the light emitting device filament 10 has a largeradius of curvature as a whole. Therefore, the shape of the lightemitting device filament 10 may be changed as a whole by adjusting thenumber of the bendable portions 113 and the lengths L1, L2, L3, L4, . .. , and Ln of the flat portions R1, R2, R3, . . . , Rn.

In the exemplary embodiment of the present disclosure, the notches 115between the flat portions R1, R2, R3, R4, . . . , and Rn are shown tohave the same size, but they should not be limited thereto or thereby.According to another exemplary embodiment of the present disclosure,each notch 115 may be provided in a different size according to an anglebetween two flat portions R1, R2, R3, R4, . . . , and Rn to be bent. Forexample, the recessed degree of one notch 115 from the lower surface ofthe substrate 110 and the width of the notch 115 may be smaller orlarger than the other notches 115.

According to the exemplary embodiment of the present disclosure, theshape and/or the bending angle of the light emitting device filament 10may be controlled by adjusting the length of each of the flat portionsR1, R2, R3, R4, . . . , and Rn, the number of the notches 115, and thesize of the notch 115. The shape and/or the bending angle of the lightemitting device filament 10 may be determined in consideration of thelight emission direction and design factors, and the light emittingdevice filament 10 may be provided in a form corresponding to the shapeof the globe 20.

In the exemplary embodiment of the present disclosure, referring to afirst flat portion R1 closest to the first end 111 a and an n-th flatportion Rn (corresponding to a fourth flat portion R4 in the drawing)closest to the second end 111 b, an angle formed between a longitudinaldirection of the first flat portion R1 and a longitudinal direction ofthe n-th flat portion Rn may be about 45 degrees to about 90 degrees.

The light emitting device chip 130 and a fluorescent substance layer 160covering the light emitting device chip 130 are provided on at least aportion of the flat portions R1, R2, R3, R4, . . . , and Rn. In thiscase, the light emitting device chip 130 is not provided in the bendableportion 113.

A connection line 150 is disposed on the flat portions R1, R2, R3, R4, .. . , and Rn and the bendable portion 113 to electrically connect thelight emitting device chips 130 in the flat portions R1, R2, R3, R4, . .. , and Rn. The connection line 150 is for applying the power to thelight emitting device chips 130. The connection line 150 may be formedon the substrate 110 in various forms. The connection line 150 may beformed in a variety of different ways that allow the electricalconnection, for example, in the form of a plating film, in the form of awire, a solder paste, a connector, and the like.

The light emitting device chip 130 is disposed on at least some of theflat portions R1, R2, R3, R4, . . . , and Rn of the substrate 110 andemits a light. The light emitted from the light emitting device chip 130may be an infrared light, an ultraviolet light, or a visible light, butit should not be particularly limited. In the exemplary embodiment ofthe present disclosure, the light emitting device chip 130 may emit thevisible light.

The light emitting device chip 130 is disposed on at least two flatportions R1, R2, R3, R4, . . . , and Rn on the substrate 110. One ormore light emitting device chips 130 may be provided for each of theflat portions R1, R2, R3, R4, . . . , and Rn and may be provided indifferent numbers for each of the flat portions R1, R2, R3, R4, . . . ,and Rn. The light emitting device chips 130 may be provided separatelyfrom each other and may be arranged in various forms on each flatportion of the substrate 110. For example, the light emitting devicechips 130 may be arranged in a line form, or a matrix form on thesubstrate 110 along a longitudinal direction of the substrate 110.However, the arrangement of the light emitting device chips 130 shouldnot be limited thereto or thereby and may be randomly arranged.

Each light emitting device chip 130 may emit lights having variouscolors. Each light emitting device chip 130 may include a variety ofelements that emits the light, and a light emitting diode according toan exemplary embodiment of the present disclosure may be used.

Each light emitting device chip 130 may emit a white light and/or acolor light. Each light emitting device chip 130 may emit one color;however, each light emitting device chip 130 may emit the white lightand/or the color light by combining different colors. In the exemplaryembodiment of the present disclosure, the light emitting device chip 130may include a red light emitting device chip, a green light emittingdevice chip, and a blue light emitting device chip. However, the coloremitted by the light emitting device chips 130 should not be limitedthereto or thereby, and each light emitting device chip 130 may emitcolors such as cyan, magenta, and yellow.

It is not necessary for each light emitting device chip 130 to usegreen, red, and/or blue light emitting device chips in order toimplement the color, and a light emitting device chip 130 emitting acolor other than the red, green, and blue light emitting device chipsmay be used. The fluorescent substance layer 160 is disposed on thelight emitting device chip 130, covers the light emitting device chip130, and converts a wavelength of the light emitted from the lightemitting device chip 130.

For example, a red light emitting diode may be used to implement the redcolor; however, the red light may be emitted by using a blue orultraviolet light emitting diode with the fluorescent substance layer160 that absorbs a blue light or ultraviolet light and then emits thered color. In the same manner, a green light emitting diode may be usedto implement the green color; however, the green light may be emitted byusing the blue or ultraviolet light emitting diode with the fluorescentsubstance layer 160 that absorbs the blue light or ultraviolet light andthen emits the green color.

The fluorescent substance layer 160 may be disposed on the substrate 110and may cover at least one light emitting device chip 130. In otherwords, the fluorescent substance layer 160 may be provided to cover eachlight emitting device chip 130, or may be provided to cover two or morelight emitting device chips 130. In the exemplary embodiment of thepresent disclosure, the fluorescent substance layer 160 is provided tocover the light emitting device chips 130 disposed on each flat portionsR1, R2, R3, . . . , and Rn; however, the present disclosure should notbe limited thereto or thereby. Two fluorescent substance layers 160spaced apart from each other may be disposed on each one of the flatportions R1, R2, R3, . . . , and Rn. In this case, however, the lightemitting chips 130 may be covered by the fluorescent substance layer 160from the top of the light emitting chips 130. According to the exemplaryembodiment of the present disclosure, if necessary, the fluorescentsubstance layer 160 may not be disposed on the light emitting devicechip 130. When the fluorescent substance layer 160 is not provided onthe light emitting device chip 130, a separate structure for protectingthe light emitting device chip 130 may be added; however, it should notbe limited thereto or thereby.

The fluorescent substance layer 160 may not be greatly restricted inshape as long as the fluorescent substance layer 160 covers the lightemitting device chip 130 and converts the color of the emitted light;however, the fluorescent substance layer 160 may be provided only on anupper surface of the substrate 110 in the exemplary embodiment of thepresent disclosure. When the fluorescent substance layer 160 is providedon the upper surface of the substrate 110, in particular, only on aportion of the upper surface of the substrate 110, a lower surface and aside surface of the substrate 110 and/or a portion of the upper surfaceof the substrate 110 are exposed to the outside, and thus, thedissipation of heat through the substrate 110 may be easily performed.Accordingly, the heat generated by the light emitting device chip 130may be effectively removed, and thus, a defective rate of the lightemitting device chip 130 may be reduced.

In the above-described embodiments, for the convenience of explanation,only the light emitting device chip 130, the connection line 150, andthe fluorescent substance layer 160 are shown on the substrate 110,however, other additional components may be further provided. Forexample, an insulating adhesive layer may be further provided betweenthe substrate 110 and the light emitting device chip 130 to attach thelight emitting device chip 130 to the substrate 110. The connection line150 may be disposed on the insulating adhesive layer, and a photo solderresist (PSR) may be further disposed between the connection line 53 andthe fluorescent substance layer 160.

The light emitting device chip 130 according to the exemplary embodimentof the present disclosure may be implemented in various ways, and FIG. 5is a cross-sectional view showing the light emitting device chip 130implemented as a light emitting diode according to an exemplaryembodiment of the present disclosure. The light emitting diode may beconfigured in various forms such as a vertical type or a flip type. Inthe present exemplary embodiment, the vertical-type light emitting diodeis shown as a representative example. However, the structure of thelight emitting diode should not be limited thereto or thereby, and thefollowing drawings should be understood as one embodiment of the presentdisclosure.

Referring to FIG. 5 , the light emitting device chip 130 is provided onthe substrate 110 with the insulating adhesive layer 120 interposedtherebetween.

The light emitting device chip 130 may include a device substrate 131, afirst conductive type semiconductor layer 133, an active layer 135, asecond conductive type semiconductor layer 139, and first and secondcontact electrodes 140 a and 140 b.

The device substrate 131 is a growth substrate 110 to grow a III-Vnitride-based semiconductor layer, and may be, for example, a sapphiresubstrate, particularly a patterned sapphire substrate. The devicesubstrate 131 is preferably an insulating substrate; however, it shouldnot be limited to the insulating substrate.

The first conductive type semiconductor layer 133, the active layer 135,and the second conductive type semiconductor layer 139 are sequentiallydisposed on the device substrate 131. The first conductive type and thesecond conductive type have opposite polarities to each other. When thefirst conductivity type is an n-type, the second conductive type is ap-type, or alternatively, when the first conductive type is the p-type,the second conductive type is the n-type. In the exemplary embodiment ofthe present disclosure, a structure in which the n-type semiconductorlayer, the active layer, and the p-type semiconductor layer aresequentially formed on the device substrate 131 will be described as arepresentative example.

The n-type semiconductor layer, the active layer, and the p-typesemiconductor layer may be formed of a III-V nitride-basedsemiconductor, for example, a nitride-based semiconductor such as (Al,Ga, In)N. The n-type semiconductor layer, the active layer, and thep-type semiconductor layer may be formed by being grown on the substrate110 in a chamber using a known method such as a metal-organic chemicalvapor deposition (MOCVD). In addition, the n-type semiconductor layerincludes n-type impurities (e.g., Si, Ge, or Sn), and the p-typesemiconductor layer includes p-type impurities (e.g., Mg, Sr, or Ba).For example, the n-type semiconductor layer may include GaN or AlGaNcontaining Si as a dopant, and the p-type semiconductor layer mayinclude GaN or AlGaN containing Mg as a dopant. Although the n-typesemiconductor layer and the p-type semiconductor layer are each shown ashaving a single-layer structure in the drawings, these layers may have amulti-layer structure and may also include a superlattice layer. Theactive layer may have a single quantum well structure or a multi-quantumwell structure, and a composition ratio of the nitride-basedsemiconductor is adjusted to emit a desired wavelength. For example, theactive layer may emit a blue light, or an ultraviolet light.

The first contact electrode 140 a is disposed on the first conductivetype semiconductor layer 133 on which the active layer 135 and thesecond conductive type semiconductor layer 139 are not provided, and thesecond contact electrode 140 b is disposed on the second conductive typesemiconductor layer 139.

The first and/or second contact electrodes 140 a and 140 b may have asingle-layer, or multi-layer structure of metals. As the material of thefirst and/or second contact electrodes 140 a and 140 b, metals such asAl, Ti, Cr, Ni, Au, and alloys thereof may be used.

In the exemplary embodiment of the present disclosure, although thelight emitting device chip 130 is briefly described with reference tothe drawings, the light emitting device chip 130 may further include alayer having additional functions in addition to the above-describedlayer. For example, an electron blocking layer 137 may be disposed onthe active layer 135. The electron blocking layer is disposed betweenthe active layer 135 and the second conductive type semiconductor layer139 and prevents electrons that are not combined with holes in theactive layer due to a relatively high energy band gap from beingdiffused to the second conductive type semiconductor layer 139 disposedthereon. The electron blocking layer 137 may include, for example,aluminum gallium nitride (AlGaN). Further, the light emitting devicechip 130 may include various layers, such as a reflective layer forreflecting a light, an additional insulating layer for insulating aspecific component, and a solder-preventing layer for preventing thesolder from being diffused.

When a forward bias is applied to the light emitting diode having theabove-mentioned structure, the electrons are combined with the holes inthe active layer 135, and the light is emitted.

Referring to FIGS. 3A to 3C and 4A to 4C again, the first contactelectrode and the second contact electrode are connected to theconnection line 150 through wires. A first power and a second power areapplied to the connection line 150. When the first power and the secondpower are applied to the first contact electrode and the second contactelectrode through the wires, the light emitting device chip 130 isdriven to emit a light.

In the exemplary embodiment of the present disclosure, an electrode pad170 connected to the connection line 150 is disposed at the first end111 a (see FIGS. 3A through 3C). The electrode pad 170 includes a firstelectrode pad 170 a and a second electrode pad 170 b, which arerespectively connected to the first contact electrode and the secondcontact electrode of the light emitting device chip 130. The first andsecond electrode pads 170 a and 170 b are disposed at the first end 111a of the substrate 110. The first and second electrode pads 170 a and170 b are disposed to be spaced apart from each other, and uppersurfaces of the first and second electrode pads 170 a and 170 b areexposed to the outside.

In the exemplary embodiment of the present disclosure, the first andsecond electrode pads 170 a and 170 b disposed at the first end 111 amay be engaged with the power board 30 in various forms to beelectrically connected to the power board 30.

For example, as shown in FIG. 4B, the upper surface of the electrode pad170 is exposed to the outside, the exposed upper surface makes contactdirectly with the wire connection portion provided in the insertion holeof the power board 30 when being inserted in the insertion hole, andthus, the power may be applied to the electrode pads 170.

In the exemplary embodiment of the present disclosure, the electrode pad170 may be provided in other forms. For example, it may be directlyattached to the exposed first and second electrode pads using aconductive adhesive member (e.g., an anisotropic adhesive, a solder,etc.).

As shown in FIG. 4C, an additional line 173 may be attached directly tothe second electrode pad 170. Referring to FIG. 4C, a conductiveadhesive member 175 may be disposed on the second electrode pad 170, andthe additional line 173 may be connected to the electrode pad 170 withthe conductive adhesive member 175 interposed therebetween. Theadditional line 173 may have various shapes, such as a wire form or aplate shape. According to the present exemplary embodiment, theelectrical connection with other components may be facilitated throughthe additional line 173.

In the exemplary embodiment of the present disclosure, the lightemitting device chips may be connected to the connection line in variousforms. FIGS. 6A and 6B are conceptual views showing the light emittingdevice chips connected to the connection line according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 6A, a plurality of light emitting device chips 130 maybe connected to a connection line 150 in parallel. According to thepresent exemplary embodiment, first contact electrodes of each lightemitting device chip 130 may be connected to the connection line 150using a wire or other connection members, and second contact electrodesof each light emitting device chip 130 may be connected to theconnection line 150 using a wire or other connection members.

Referring to FIG. 6B, a plurality of light emitting device chips 130 maybe connected to a connection line 150 in series. According to thepresent exemplary embodiment, the light emitting device chips 130 andthe connection line 150 may be connected in series by connecting theconnection line 150 connected to an electrode pad 170 to a first contactelectrode of an adjacent light emitting device chip 130 and byconnecting a second contact electrode of the adjacent light emittingdevice chip 130 to a first contact electrode of an adjacent lightemitting device chip 130 via a connection line 150 on the opposite side.

Although not shown in figures, different from the embodiments shown inFIGS. 6A and 6B, the light emitting device chip 130 may be arranged in acombination of serial and parallel connections. The connection method ofthe light emitting device chips 130 may be modified in various ways bytaking into account a current applied thereto or an amount of lightemitted therefrom. In addition, the connection line 150 is entirelyconnected to the light emitting device chips 130, but it should not belimited thereto or thereby. That is, a plurality of connection lines 150to which a power is individually supplied may be separately provided.For example, in the exemplary embodiment of the present disclosure, allthe light emitting device chips 130 provided in the first, second,third, and fourth flat portions R1, R2, R3, and R4 are directly orindirectly connected to each other. However, according to anotherembodiment, only the light emitting device chips 130 corresponding toeach one of the flat portions R1, R2, R3, R4, . . . , and Rn, i.e., thesame flat portion, may be directly or indirectly connected to eachother, and the light emitting device chips 130 corresponding todifferent flat portions R1, R2, R3, R4, . . . , and Rn may beindividually operated without being connected to each other.

In the exemplary embodiment of the present disclosure, as the substrateof the filament is formed not of a glass or ceramic material but of ametal material, the heat generated by the light emitting device chip maybe effectively dispersed. Accordingly, due to the heat dissipationeffect of the light emitting device chip, deterioration of the lightemitting device chip may be prevented. In a conventional bulb-type lightsource, when a substrate used for the light emitting device filament isformed of the glass or ceramic material, it is necessary to fill ahelium gas as a heat transfer medium in the globe for the heatdissipation. However, according to the exemplary embodiment of thepresent disclosure, the heat dissipation effect may be increased byusing the metal substrate, and thus, there is no need to fill a heatdissipation gas, such as the helium gas, in the globe. Therefore, amanufacturing method of the bulb-type light source is simplified, and amanufacturing cost of the bulb-type light source is reduced. Inaddition, when the substrate is formed of the metal material, the lightemitted from the light emitting device chip may be effectively scatteredand/or reflected, and thus, the light emission efficiency may beimproved.

As described above, as the bulb-type light source according to theexemplary embodiment of the present disclosure includes the lightemitting device filament that is bent multiple times, the light emissionarea is significantly expanded, compared with the conventional bulb-typelight source.

Even when a light emitting device filament is used to emit the light ina conventional bulb-type light source, the light emitting devicefilament of the conventional bulb-type light source is provided in astraight-line shape. In the case of the light emitting device filamentprovided in the straight-line shape, the light is emitted only in onedirection that is perpendicular to the straight line. As a result, thelight is hardly emitted in a direction parallel to the straight line,that is, the light is hardly emitted to both ends in a direction inwhich the light emitting device filament extends. Consequently, in thelight emitting device filament of the straight-line shape, there areareas in which the amount of the light significantly decreases along apredetermined direction.

However, since the light emitting device filament according to theexemplary embodiment of the present disclosure includes the bendableportion, the light emitting device filament may be bent in variousdirections, and the light may be emitted in various directions ratherthan one direction. In addition, in the exemplary embodiment of thepresent disclosure, as the light emitting device filament is bendable,curved, or flexed in various directions or a plurality of bent lightemitting device filaments is provided, the light may be uniformlyemitted in all directions without reducing the amount of light in aspecific direction. In particular, when the light emitting devicefilament according to the exemplary embodiment of the present disclosureis used, the amount of the light traveling upward along the extensiondirection of the central axis may be significantly increased.

FIG. 7 is a side cross-sectional view showing a portion of a bulb-typelight source employing a light emitting device filament according to anexemplary embodiment of the present disclosure with a travelingdirection of a light emitted from a light emitting device in the lightemitting device filament.

Referring to FIG. 7 , the bulb-type light source according to theexemplary embodiment includes the bendable portion, and thus, the lightemitting device filament 10 may be bent in various directions.Particularly, since the second end 111 b of the bendable portion is bentthrough the notch, the extension direction thereof may be close to thedirection perpendicular to the direction in which the central axispasses. Accordingly, the emission angle of the light emitted from lightemitting devices in the light emitting device filament 10 is alsochanged in accordance with the arrangement direction of the second end111 b of the bendable portion. For example, when the light emittingdevice disposed on the second end 111 b emits a light having apredetermined orientation angle θ, the light emitted from the second end111 b of the light emitting device filament 10 travels to an area shownin FIG. 7 , i.e., to an upper portion and an area slightly inclined fromthe upper portion (an area within an angle indicated by θ). Here, whenthe light emitting device filament 10 is provided in plural numbers,there exists an area in which traveling directions of the light emittedfrom the light emitting device filaments 10 overlap each other, and darkspots are not visible since a sufficient amount of light travels in theoverlapping area. Particularly, according to the exemplary embodiment ofthe present disclosure, when lights emitted from adjacent light emittingdevice filaments 10 facing each other travel symmetrically with anorientation angle of θ, a distance a1 from the fixing plate 11 to theoverlapping area of the lights emitted from the two filaments is smallerthan a distance a2 from the fixing plate 11 to the globe 20, and thus,the dark spots in the upward direction of the bulb-type light sourcepractically rarely occur.

This is explained in more detail as follows. In general, since the lightemitting device filament is mounted on the substrate in a state where anindividual light emitting device chip mounted on the light emittingdevice filament has a predetermined orientation angle (for example, fromabout 90 degrees to less than about 180 degrees, or from about 120 toabout 150 degrees), the emission direction of the light may varydepending on the shape of the light emitting device filament. In thecase where the light emitting device filament has the straight-lineshape as the conventional light emitting device filament, the lightemitted from the light emitting device chips is emitted only in acertain direction. As a result, the amount of the light is maximum inthe direction perpendicular to the extension direction of the lightemitting device filament, and the amount of the light is significantlyreduced in the extension direction of the light emitting device filamentand the opposite direction to the extension direction of the lightemitting device filament.

Although the light emitting device filament according to the exemplaryembodiment of the present disclosure includes the light emitting devicechip having the predetermined orientation angle, the traveling directionof the light from the individual light emitting device chip in the lightemitting device filament is variously expanded since the light emittingdevice filament is bent at various angles.

In other words, the light emitting device filament of the presentdisclosure has the bendable or curved shape at multiple positions to besubstantially perpendicular or to be inclined to the extension directionof the central axis when the light emitting device filament extendsalong the central axis. The light emitting device chips are arrangedalong the bendable shape and emit the light entirely from the extensiondirection of the central axis to the opposite direction to the extensiondirection with respect to the central axis. Accordingly, the lightemitting device filament of the present disclosure may provide thesubstantially uniform light from front to back along the extensiondirection of the central axis and over substantially 360 degrees alongthe direction perpendicular to the extension direction of the centralaxis.

Consequently, as the light emitting device filaments are bendable orcurved, the individual light emitting device chips are directed invarious directions and finally emit the light while covering a largearea. In this case, the degree of bending of the substrate at thebendable portion may be adjusted according to the orientation angle ofthe individual light emitting device chip.

In addition, since the light emitting device filament according to theexemplary embodiment of the present disclosure may be formed of arelatively rigid material to have the flat shape at the flat portionother than the bent portion, it is easy to control the curvature in theoverall shape. When the substrate is formed of a flexible material, itis difficult to control the angle at which the light emitting devicefilament is bent, and thus, it is not easy to form the light emittingdevice filament into a desired shape. In addition, when the substrate isformed of the flexible material, the substrate is easily deformed due toexternal impacts. In order to easily control the curvature while usingthe rigid substrate, the thickness of the substrate may be reduced.However, when the thickness of the substrate is reduced by more than apredetermined degree, the amount of heat that can dissipate through thesubstrate is also reduced, thereby decreasing the heat dissipationeffect.

However, as the light emitting device filament according to theexemplary embodiment of the present disclosure may be bent at anappropriate degree by the bendable portion, the overall shape may becontrolled. In addition, since the light emitting device filament is notflexible, the shape of the light emitting device filament is also lesslikely to be deformed by the external impacts. Further, the substrate iseasily bendable while having the thickness with a predetermined degreeor more due to the bendable portion, and the shape of the light emittingdevice filament may be easily changed and the heat dissipation effectmay be improved

According to the exemplary embodiment of the present disclosure, thebulb-type light source having the above-described shape may employ astructure for preventing disconnection at the bendable portion.

FIGS. 8A and 8B are perspective views showing a bendable portion 113 andtwo flat portions adjacent to the bendable portion 113 of a bulb-typelight source according to an exemplary embodiment of the presentdisclosure. FIGS. 8A and 8B show that the substrate 110 is bent at thebendable portion 113, and some components are omitted. Hereinafter,different features from the above-mentioned features will be mainlydescribed in order to avoid redundancy.

Referring to FIGS. 8A and 8B, the substrate 110 includes the bendableportion 113 in which a notch 115 is formed and the flat portionsdisposed at both sides of the bendable portion 113.

A light emitting device chip 130 (not shown), a connection line 150connecting each light emitting device chip (not shown) to adjacent lightemitting device chip, and a fluorescent substance layer 160 covering thelight emitting device chip 130 are formed at each flat portion of thesubstrate 110. In the present exemplary embodiment, the light emittingdevice chip 130 and the fluorescent substance layer 160 are disposedonly on each flat portion and not disposed on the bendable portion 113.

The notch 115 is formed in a lower surface of the substrate 110, and thesubstrate 110 is bent downward with respect to the notch 115 of thebendable portion 113. As the substrate 110 is bent downward with respectto the bendable portion 113, an upper surface of the substrate 110corresponding to the bendable portion 113 is bent, and a tensile stressis applied to components disposed on the upper surface of the substrate110. Accordingly, lines disposed on the bendable portion 113 may bedisconnected by the tensile stress.

In the exemplary embodiment of the present disclosure, in order toreduce the disconnection of the connection line 150 due to the tensilestress of the bendable portion 113, a width, or a shape of theconnection line 150 may be set differently. For example, as shown inFIG. 8A, when the width of the lines in the bendable portion 113increases, even though a defect such as a crack occurs in some portionsof the lines, the disconnection may be prevented by connecting the linesby remaining portions of the lines. As another example, as shown in FIG.8B, the connection line 150 may have a zigzag shape in the bendableportion 113. When the connection line 150 is disposed to be inclined toa direction to which the tensile stress is applied in the zigzag shape,the applied stress is reduced. Therefore, the disconnection of theconnection line 150 in the bendable portion 113 may be prevented.

According to the exemplary embodiment of the present disclosure, thebendable portion 113 may be modified in various ways to facilitate thebending of the light emitting device filament 10. FIGS. 9A to 9E arecross-sectional views showing various types of bendable portions 113.For the convenience of explanation, FIGS. 9A to 9E show only a substrate110 and a notch 115, and others are omitted.

Referring to FIGS. 9A to 9E, the bendable portion 113 may have variouscross-sectional shapes. For example, the bendable portion 113 may have asemi-circular shape as shown in FIG. 9A or may have a rectangular shapeas shown in FIG. 9B.

In addition, one notch 115 is provided in the bendable portion, however,as shown in FIG. 9C, two or more notches 115 may be continuouslyarranged in the bendable portion.

Further, the notch 115 may be disposed on an upper surface as well as alower surface. That is, since the surface provided with the notch 115may be folded concavely or convexly in any direction, the notch 115 maybe formed in a direction that is easy to bend. For example, the notch115 may be disposed on the upper surface as shown in FIG. 9D, or thenotch 115 may be formed on both the upper surface and the lower surfaceas shown in FIG. 9E.

As described above, the notch 115 may be provided in various shapes,various numbers, and various positions depending on the shape of thedesired light emitting device filament.

In the exemplary embodiment of the present disclosure, the fluorescentsubstance layer may be provided in various shapes. FIGS. 10A to 10C areviews showing a light emitting device filament according to anotherexemplary embodiment of the present disclosure. FIG. 10A is a plan viewshowing the light emitting device filament, and FIGS. 10B and 10C areside views showing the light emitting device filament.

Referring to FIGS. 10A to 10C, in a light emitting device chip 130according to another exemplary embodiment of the present disclosure, afluorescent substance layer 160 is disposed on a bendable portion 113and flat portions respectively disposed at both sides of the bendableportion 113. In other words, the fluorescent substance layer 160 extendsfrom the flat portion and is disposed on the bend portion 113.

As a substrate 110 is bent at the bendable portion 113, the fluorescentsubstance layer 160 disposed on the substrate 110 also has a bent shapeat the bendable portion 113. In this case, an upper surface of thesubstrate 110 is bent convexly, and the fluorescent substance layer 160is bent in a convex shape along the upper surface of the substrate 110.The fluorescent substance layer 160 is bent and subjected to a tensilestress at both sides thereof. Accordingly, the fluorescent substancelayer 160 has a shape that stretches to the both sides at the bendableportion 113 and is thinner than the fluorescent substance layer 160 ofeach flat portion. Therefore, the fluorescent substance layer 160 hasdifferent thicknesses at the flat portion and the bendable portion 113.In addition, although not shown in figures, an insulating adhesive, aconnection line 150, and a photo solder paste may be further providedbetween the substrate 110 and the fluorescent substance layer 160. Theinsulating adhesive, the connection line 150, and the photo solder pastehave the bent shape at the bendable portion 113 and have differentthicknesses at the flat portion and the bendable portion 113.

In the exemplary embodiment of the present disclosure, the fluorescentsubstance layer 160 may include a material having elasticity, and thus,cutting or excessive bending of the fluorescent substance layer 160 maybe reduced when the substrate 110 is bent.

According to the exemplary embodiment of the present disclosure, thebendable portion may be formed along a width direction as well as alongitudinal direction of the light emitting device filament. FIG. 11Ais a plan view showing a light emitting device filament according toanother exemplary embodiment of the present disclosure, and FIG. 11B isa cross-sectional view taken along a line I-I′ of FIG. 11A.

Referring to FIGS. 11A and 11B, the bendable portion may be bent in awidth direction of a light emitting device filament, or alternatively ina longitudinal direction of the light emitting device filament. That is,the bendable portion may include a bendable portion 113 perpendicular toan extension direction of a substrate 110 and a bendable portion 113′parallel to the extension direction of the substrate 110. Accordingly,the substrate 110 of the light emitting device filament may be bentalong both the longitudinal direction and the width direction of thesubstrate 110. As the bendable portion is provided in various forms, adegree of freedom in the shape of the bendable portion increases.

In the present exemplary embodiment, a light emitting device chip 130and a fluorescent substance layer may not be formed in areas in whichthe bendable portions 113 and 113′ are formed. In this case, thefluorescent substance layer may be divided into a first fluorescentsubstance layer 160 a and a second fluorescent substance layer 160 bspaced apart from each other with the bendable portion 113 disposedtherebetween.

When plural fluorescent substance layers are provided and thefluorescent substance layers are spaced apart from each other, thefluorescent substance layers may convert a specific light into lightshaving the same color as each other, or may convert the specific lightinto lights having different colors from each other.

FIG. 12A is a plan view showing a light emitting device filamentaccording to an exemplary embodiment of the present disclosure, and FIG.12B is a view showing a bulb-type light source manufactured using thelight emitting device filament of FIG. 12A.

Referring to FIGS. 12A and 12B, a bendable portion 113″ may be disposedto be inclined with respect to a longitudinal direction or a widthdirection of a light emitting device filament 10 rather than thelongitudinal direction or the width direction of the light emittingdevice filament 10. When the bendable portion 113″ is inclined withrespect to the longitudinal direction or the width direction, the lightemitting device filament is bent in an oblique direction. Accordingly, aspiral-shaped filament may be implemented as shown in FIG. 12B. Thespiral-shaped filament may emit the light in various directions as wellas a certain direction, and thus, uniformity of the light may beenhanced.

According to an exemplary embodiment of the present disclosure, a shapeof the globe may be changed in various forms. FIGS. 13A to 13C arecross-sectional views showing various types of globes 20.

Referring to FIGS. 13A to 13C, the globe 20 may have a radius thatincreases or decreases along a central axis as a distance from a socket40 increases. Alternatively, the radius may be maintained and then mayincrease or decrease. The shape of the globe 20 may vary according tovarious designs. The shape of the light emitting device filament 10 mayvary depending on the shape of the globe 20. When the radius from thecentral axis of the globe 20 is large, the degree of bending of thelight emitting device filament 10 may also increase, and when the radiusfrom the central axis of the globe 20 is small, the degree of bending ofthe light emitting device filament 10 may also decrease.

According to an exemplary embodiment of the present disclosure, theconnection relation between the light emitting device filament and thepower board may be provided differently from the above-describedembodiment. FIG. 14 is a view showing a bulb-type light source accordingto an exemplary embodiment of the present disclosure, and instead offorming an electrode pad at a first end 111 a of a light emitting devicefilament, a wire electrode 171 is provided. In the exemplary embodimentof the present disclosure, the wire electrode 171 may be connected to aline unit in a socket 40. As described above, the light emitting devicefilament may be supplied with power from the line unit in various ways,and a power supply method may be changed in various ways as necessary.

According to the exemplary embodiment of the present disclosure, as thefilament having the straight-line shape is easily bent using the notch,the light emitting device filament having various shapes may bemanufactured. In the exemplary embodiment of the present disclosure,when several filaments having the straight-line shape are provided, theseveral filaments having the straight-line shape may be bentsimultaneously by fixing the second end at the angle “θ” and thenpushing the first ends in the direction toward the second endsimultaneously. For example, after inserting several filaments, whichare not yet bent and have the straight-line shape, into the globe, thefilament having the straight-line shape may be bent into a specificshape by pushing one end of the filament having the straight-line shapeinwardly. In this case, since the light emitting device filament is bentin the globe, it is possible to manufacture the light emitting devicefilament that is wider than the opening of the globe.

Although the exemplary embodiments of the present disclosure have beendescribed, it is understood that the present disclosure should not belimited to these exemplary embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present disclosure as hereinafter claimed.

Therefore, the disclosed subject matter should not be limited to anysingle embodiment described herein, and the scope of the presentinventive concept shall be determined according to the attached claims.

According to the exemplary embodiment of the present disclosure, thebulb-type light source with the shape similar to that of theconventional bulb but with the high light uniformity in all directionsis provided.

The invention claimed is:
 1. A lighting device comprising: a substratecomprising a plurality of flat portions and a non-flat portion disposedbetween two neighboring flat portions among the plurality of flatportions; a plurality of light emitting sources disposed on theplurality of flat portions of the substrate; a fluorescent substratelayer covering one or more light emitting sources of the plurality oflight emitting sources and converting a wavelength of light emitted fromthe one or more light emitting sources; and a connection line disposedon the non-flat portion of the substrate and electrically connectingadjacent light emitting sources arranged on the two neighboring flatportions, wherein the substrate has a first end and a second end thatare arranged at different distance from a central axis; and theplurality of flat portions includes a first flat portion and a secondflat portion that are different in length between the first end and thesecond end.
 2. The lighting device of claim 1, further comprising aglobe to transmit the light emitted from the one or more light emittingsources.
 3. The lighting device of claim 2, further comprising: a socketengaged with the globe; and a power board disposed in the socket andconnected to the light emitting source.
 4. The lighting device of claim3, wherein the first end of the substrate is connected to the powerboard, and the second end of the substrate is spaced apart from thepower board.
 5. The lighting device of claim 4, wherein an electrode padis disposed at the first end to supply power to the light emittingsources.
 6. The lighting device of claim 3, further comprising a fixingplate that fixes the second end.
 7. The lighting device of claim 6,wherein: each light emitting source emits light with an orientationangle in two or more light emission areas; two light emission areas arepositioned at the second end adjacent to each other and overlap witheach other; and a distance from the fixing plate to an overlapping areais smaller than a distance from the fixing plate to the globe.
 8. Thelighting device of 2, wherein the plurality of light emitting sourcesare arranged radially about a center of the globe when viewed from onedirection.
 9. The lighting device of claim 1, wherein the first end ofthe substrate is farther away from the center than the second end of thesubstrate is.
 10. The lighting device of claim 1, wherein the substrateis farther away from the center at a position between the first andsecond ends than from the first and second ends.
 11. A lighting devicecomprising: a globe transmitting a light; a substrate comprising aplurality of flat portions and at least one of non-flat portion; aplurality of light emitting sources disposed on the substrate; afluorescent substrate layer covering one or more light emitting sourcesand converting a wavelength of light from the one or more light emittingsources; and a connection line disposed on the substrate andelectrically connecting adjacent light emitting sources; wherein thesubstrate has a first end and a second end, the first end and the secondend arranged at different distance from a central axis; and a fixingplate that fixes the second end; wherein: each light emitting sourceemits light with an orientation angle in two or more light emissionareas; two light emission areas are positioned at the second endadjacent to each other and overlap with each other; and a distance fromthe fixing plate to an overlapping area is smaller than a distance fromthe fixing plate to the globe.
 12. The lighting device of claim 11,further comprising: a socket engaged with the globe; and a power boarddisposed in the socket and connected to the plurality of light emittingsources.
 13. The lighting device of claim 12, wherein the first end ofthe substrate is connected to the power board, and the second end of thesubstrate is spaced apart from the power board.
 14. The lighting deviceof claim 13, wherein an electrode pad is disposed at the first end tosupply a power to the light emitting sources.
 15. The lighting device ofclaim 14, wherein the power board is provided with an insertion holeinto which the first end is inserted, and the power is supplied to thelight emitting sources through the electrode pad when the first end isinserted into the insertion hole.
 16. The lighting device of claim 11,wherein the plurality of light emitting sources are arranged radiallyabout a center of the globe when viewed from one direction.
 17. Thelighting device of claim 11, wherein the first end of the substrate isfarther away from a center of the globe than the second end of thesubstrate is.
 18. The lighting device of claim 11, wherein the substrateis farther away from the center at a position between the first andsecond ends than from the first and second ends.
 19. A lighting devicecomprising: a plurality of light filaments coupled at a first end and asecond end and extending along a central axis, a light filamentcomprising: a substrate comprising a plurality of flat portions and anon-flat portion disposed between two neighboring flat portions amongthe plurality of flat portions; a plurality of light emitting sourcesdisposed on the plurality of flat portions of the substrate; afluorescent substrate layer covering one or more light emitting sourcesand converting a wavelength of light from the plurality of lightemitting sources; and a connection line disposed on the non-flat portionof the substrate and electrically connecting the one or more lightemitting sources arranged on the two neighboring flat portions, whereinamong a first distance between the central axis and the light filamentat the first end, a second distance between the central axis and thelight filament at the second end, and a third distance between thecentral axis and the light filament in an area between the first end andthe second end, the third distance is greater than the first distanceand the second distance such that an influence of heat between theplurality of light filaments adjacent to each other is minimized. 20.The lighting device of claim 19, further comprising a globe having adiameter that is the largest in an area corresponding to the areabetween the first end and the second end, wherein the light filament isarranged to be the farthest away from the central axis in the areabetween the first end and the second end.